2.86f has the new feature that the filter expression is not evaluated immediately, this is more comfortable for larger collections.
The filter application has now to be confirmed with Enter.
Under the following circumstances the display of the filter and that of the data is not quite in sync:
Enable the new feature.
Enter a filter.
Press enter to apply the filter - watch the status bar that the number of displayed items is lower than the number of loaded ones.
Delete the filter BUT do not press enter. The current filter remains active.
Close MP3tag, re-open it: the filter is displayed again and active. (In a way this seems plausible to me, although the same thing is shown in 2 ways).
Setup the situation the situation just like before Case 1.
This time: press F3 to disable the filter.
Result: the filter remains active, the numbers in the status bar do not change. This looks like a bug to me.
Press F3 again, to enable the filter.
The filter box remains empty (not like after closing and opening MP3tag in Case 1) but the filter is still active (check status bar). This also looks like a bug to me or at least like a function that has not been conclusively developed.
The good thing: if you close and open MP3tag in this state, you see the filter again.